Decontamination of laundry exposed to Microsporum canis hairs and spores.

OBJECTIVES: The objective of this study was to determine the efficacy of decontamination of fabric exposed to Microsporum canis hairs and spores by mechanical washing using hot or cold water with or without a sodium hypochlorite additive, and to field test a washing protocol for terry cloth and denim exposed to M canis via direct contact with infected cats.

METHODS: Cotton, terry cloth and denim fabric swatches were contaminated with isolated infective spores and hairs and then washed in water at temperatures of 30°C and 60°C, with and without a sodium hypochlorite additive, and with and without mechanical drying. Terry cloth and denim were contaminated by direct contact with infected kittens and washed at 30°C until culture-negative.

RESULTS: All prelaundering samples had >300 colony forming units (cfu)/plate. Experimentally contaminated fabrics were culture-negative, regardless of fabric type, water temperature, the presence or absence of sodium hypochlorite, or tumble drying after one wash. After one wash, 22/34 (65%) of terry cloth towels and 12/20 (60%) denim fabric squares were culture-positive, but the infective load was minimal (1-5 cfu/plate). After two washes in cold water there was no detectable contamination of fabric. The rinse water was not contaminated with spores. The laundry tub was easily decontaminated via mechanical cleaning followed by use of a disinfectant.

CONCLUSIONS AND RELEVANCE: Washable textiles exposed to M canis can be decontaminated via mechanical washes in cold water without the addition of bleach. Two washes are recommended to ensure removal of spores. Laundry can be effectively decontaminated by washing twice in cold water on a long wash cycle (for ⩾14 mins). It is important to ensure maximal agitation (ie, the machine should not be overloaded).